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class="btn-ok btn-link" data-v-40eb6fce="">前往小册首页</div></div></div><div class="model fail" style="display:none;" data-v-40eb6fce=""><div class="heading" data-v-40eb6fce="">领取失败</div><div class="content-text" data-v-40eb6fce="">本活动仅适用于小册新用户</div><div class="btn-ok" data-v-40eb6fce="">知道了</div></div></div><!----></div><!----><div data-v-25b273c2="" data-v-c5c2a81e="" class="book-read-view"><section data-v-25b273c2="" class="book-section"><div data-v-25b273c2="" class="book-summary"><div data-v-25b273c2="" class="book-summary-masker"></div><div data-v-25b273c2="" class="book-summary-inner"><div data-v-25b273c2="" class="book-summary__header"><a data-v-25b273c2="" href="https://juejin.im/books" target="" rel="" class="logo"><img data-v-25b273c2="" src="./14.安全防范知识点_files/logo.a7995ad.svg"></a><div data-v-25b273c2="" class="label">小册</div><!----></div><!----><div data-v-d0eb2184="" data-v-25b273c2="" class="book-directory book-directory bought"><a data-v-d0eb2184="" class="section section-link read"><div data-v-d0eb2184="" class="step"><div data-v-d0eb2184="" class="step-btn">1</div></div><div data-v-d0eb2184="" class="center"><div data-v-d0eb2184="" class="title">小册食用指南</div><!----><!----></div><!----></a><a data-v-d0eb2184="" class="section section-link read"><div data-v-d0eb2184="" class="step"><div data-v-d0eb2184="" class="step-btn">2</div></div><div data-v-d0eb2184="" class="center"><div data-v-d0eb2184="" class="title">JS 基础知识点及常考面试题（一）</div><!----><!----></div><!----></a><a data-v-d0eb2184="" class="section section-link read"><div data-v-d0eb2184="" class="step"><div data-v-d0eb2184="" class="step-btn">3</div></div><div data-v-d0eb2184="" class="center"><div data-v-d0eb2184="" class="title">JS 基础知识点及常考面试题（二）</div><!----><!----></div><!----></a><a data-v-d0eb2184="" class="section section-link read"><div data-v-d0eb2184="" class="step"><div data-v-d0eb2184="" class="step-btn">4</div></div><div data-v-d0eb2184="" class="center"><div data-v-d0eb2184="" class="title">ES6 知识点及常考面试题</div><!----><!----></div><!----></a><a data-v-d0eb2184="" class="section section-link read"><div data-v-d0eb2184="" class="step"><div data-v-d0eb2184="" class="step-btn">5</div></div><div data-v-d0eb2184="" class="center"><div data-v-d0eb2184="" class="title">JS 异步编程及常考面试题</div><!----><!----></div><!----></a><a data-v-d0eb2184="" class="section section-link read"><div data-v-d0eb2184="" class="step"><div data-v-d0eb2184="" class="step-btn">6</div></div><div data-v-d0eb2184="" class="center"><div data-v-d0eb2184="" class="title">手写 Promise</div><!----><!----></div><!----></a><a data-v-d0eb2184="" class="section section-link read"><div data-v-d0eb2184="" class="step"><div data-v-d0eb2184="" class="step-btn">7</div></div><div data-v-d0eb2184="" class="center"><div data-v-d0eb2184="" class="title">Event Loop</div><!----><!----></div><!----></a><a data-v-d0eb2184="" class="section section-link read"><div data-v-d0eb2184="" class="step"><div data-v-d0eb2184="" class="step-btn">8</div></div><div data-v-d0eb2184="" class="center"><div data-v-d0eb2184="" class="title">JS 进阶知识点及常考面试题</div><!----><!----></div><!----></a><a data-v-d0eb2184="" class="section section-link read"><div data-v-d0eb2184="" class="step"><div data-v-d0eb2184="" class="step-btn">9</div></div><div data-v-d0eb2184="" class="center"><div data-v-d0eb2184="" class="title">JS 思考题</div><!----><!----></div><!----></a><a data-v-d0eb2184="" class="section section-link read"><div data-v-d0eb2184="" class="step"><div data-v-d0eb2184="" class="step-btn">10</div></div><div data-v-d0eb2184="" class="center"><div data-v-d0eb2184="" class="title">DevTools Tips</div><!----><!----></div><!----></a><a data-v-d0eb2184="" class="section section-link read"><div data-v-d0eb2184="" class="step"><div data-v-d0eb2184="" class="step-btn">11</div></div><div data-v-d0eb2184="" class="center"><div data-v-d0eb2184="" class="title">浏览器基础知识点及常考面试题</div><!----><!----></div><!----></a><a data-v-d0eb2184="" class="section section-link read"><div data-v-d0eb2184="" class="step"><div data-v-d0eb2184="" class="step-btn">12</div></div><div data-v-d0eb2184="" class="center"><div data-v-d0eb2184="" class="title">浏览器缓存机制</div><!----><!----></div><!----></a><a data-v-d0eb2184="" class="section section-link read"><div data-v-d0eb2184="" class="step"><div data-v-d0eb2184="" class="step-btn">13</div></div><div data-v-d0eb2184="" class="center"><div data-v-d0eb2184="" class="title">浏览器渲染原理</div><!----><!----></div><!----></a><a data-v-d0eb2184="" class="section route-active section-link"><div data-v-d0eb2184="" class="step"><div data-v-d0eb2184="" class="step-btn">14</div></div><div data-v-d0eb2184="" class="center"><div data-v-d0eb2184="" class="title">安全防范知识点</div><!----><!----></div><!----></a><a data-v-d0eb2184="" class="section section-link"><div data-v-d0eb2184="" class="step"><div data-v-d0eb2184="" class="step-btn">15</div></div><div data-v-d0eb2184="" class="center"><div data-v-d0eb2184="" class="title">从 V8 中看 JS 性能优化</div><!----><!----></div><!----></a><a data-v-d0eb2184="" class="section section-link"><div data-v-d0eb2184="" class="step"><div data-v-d0eb2184="" class="step-btn">16</div></div><div data-v-d0eb2184="" class="center"><div data-v-d0eb2184="" class="title">性能优化琐碎事</div><!----><!----></div><!----></a><a data-v-d0eb2184="" class="section section-link"><div data-v-d0eb2184="" class="step"><div data-v-d0eb2184="" class="step-btn">17</div></div><div data-v-d0eb2184="" class="center"><div data-v-d0eb2184="" class="title">Webpack 性能优化</div><!----><!----></div><!----></a><a data-v-d0eb2184="" class="section section-link"><div data-v-d0eb2184="" class="step"><div data-v-d0eb2184="" class="step-btn">18</div></div><div data-v-d0eb2184="" class="center"><div data-v-d0eb2184="" class="title">实现小型打包工具</div><!----><!----></div><!----></a><a data-v-d0eb2184="" class="section section-link"><div data-v-d0eb2184="" class="step"><div data-v-d0eb2184="" class="step-btn">19</div></div><div data-v-d0eb2184="" class="center"><div data-v-d0eb2184="" class="title">React 和 Vue 两大框架之间的相爱相杀</div><!----><!----></div><!----></a><a data-v-d0eb2184="" class="section section-link"><div data-v-d0eb2184="" class="step"><div data-v-d0eb2184="" class="step-btn">20</div></div><div data-v-d0eb2184="" class="center"><div data-v-d0eb2184="" class="title">Vue 常考基础知识点</div><!----><!----></div><!----></a><a data-v-d0eb2184="" class="section section-link"><div data-v-d0eb2184="" class="step"><div data-v-d0eb2184="" class="step-btn">21</div></div><div data-v-d0eb2184="" class="center"><div data-v-d0eb2184="" class="title">Vue 常考进阶知识点</div><!----><!----></div><!----></a><a data-v-d0eb2184="" class="section section-link"><div data-v-d0eb2184="" class="step"><div data-v-d0eb2184="" class="step-btn">22</div></div><div data-v-d0eb2184="" class="center"><div data-v-d0eb2184="" class="title">React 常用知识点</div><!----><div data-v-d0eb2184="" class="sub-line"><div data-v-d0eb2184="" class="writing">写作中...</div></div></div><!----></a><a data-v-d0eb2184="" class="section section-link"><div data-v-d0eb2184="" class="step"><div data-v-d0eb2184="" class="step-btn">23</div></div><div data-v-d0eb2184="" class="center"><div data-v-d0eb2184="" class="title">React 进阶</div><!----><div data-v-d0eb2184="" class="sub-line"><div data-v-d0eb2184="" class="writing">写作中...</div></div></div><!----></a><a data-v-d0eb2184="" class="section section-link"><div data-v-d0eb2184="" class="step"><div data-v-d0eb2184="" class="step-btn">24</div></div><div data-v-d0eb2184="" class="center"><div data-v-d0eb2184="" class="title">监控</div><!----><div data-v-d0eb2184="" class="sub-line"><div data-v-d0eb2184="" class="writing">写作中...</div></div></div><!----></a><a data-v-d0eb2184="" class="section section-link"><div data-v-d0eb2184="" class="step"><div data-v-d0eb2184="" class="step-btn">25</div></div><div data-v-d0eb2184="" class="center"><div data-v-d0eb2184="" class="title">TCP / UDP</div><!----><div data-v-d0eb2184="" class="sub-line"><div data-v-d0eb2184="" class="writing">写作中...</div></div></div><!----></a><a data-v-d0eb2184="" class="section section-link"><div data-v-d0eb2184="" class="step"><div data-v-d0eb2184="" class="step-btn">26</div></div><div data-v-d0eb2184="" class="center"><div data-v-d0eb2184="" class="title">HTTP 及 TLS</div><!----><div data-v-d0eb2184="" class="sub-line"><div data-v-d0eb2184="" class="writing">写作中...</div></div></div><!----></a><a data-v-d0eb2184="" class="section section-link"><div data-v-d0eb2184="" class="step"><div data-v-d0eb2184="" class="step-btn">27</div></div><div data-v-d0eb2184="" class="center"><div data-v-d0eb2184="" class="title">HTTP 2.0</div><!----><div data-v-d0eb2184="" class="sub-line"><div data-v-d0eb2184="" class="writing">写作中...</div></div></div><!----></a><a data-v-d0eb2184="" class="section section-link"><div data-v-d0eb2184="" class="step"><div data-v-d0eb2184="" class="step-btn">28</div></div><div data-v-d0eb2184="" class="center"><div data-v-d0eb2184="" class="title">输入 URL 到页面渲染的整个流程</div><!----><div data-v-d0eb2184="" class="sub-line"><div data-v-d0eb2184="" class="writing">写作中...</div></div></div><!----></a><a data-v-d0eb2184="" class="section section-link"><div data-v-d0eb2184="" class="step"><div data-v-d0eb2184="" class="step-btn">29</div></div><div data-v-d0eb2184="" class="center"><div data-v-d0eb2184="" class="title">设计模式</div><!----><div data-v-d0eb2184="" class="sub-line"><div data-v-d0eb2184="" class="writing">写作中...</div></div></div><!----></a><a data-v-d0eb2184="" class="section section-link"><div data-v-d0eb2184="" class="step"><div data-v-d0eb2184="" class="step-btn">30</div></div><div data-v-d0eb2184="" class="center"><div data-v-d0eb2184="" class="title">常见数据结构</div><!----><div data-v-d0eb2184="" class="sub-line"><div data-v-d0eb2184="" class="writing">写作中...</div></div></div><!----></a><a data-v-d0eb2184="" class="section section-link"><div data-v-d0eb2184="" class="step"><div data-v-d0eb2184="" class="step-btn">31</div></div><div data-v-d0eb2184="" class="center"><div data-v-d0eb2184="" class="title">常考算法题解析</div><!----><div data-v-d0eb2184="" class="sub-line"><div data-v-d0eb2184="" class="writing">写作中...</div></div></div><!----></a><a data-v-d0eb2184="" class="section section-link"><div data-v-d0eb2184="" class="step"><div data-v-d0eb2184="" class="step-btn">32</div></div><div data-v-d0eb2184="" class="center"><div data-v-d0eb2184="" class="title">CSS 常考面试题解析</div><!----><div data-v-d0eb2184="" class="sub-line"><div data-v-d0eb2184="" class="writing">写作中...</div></div></div><!----></a><a data-v-d0eb2184="" class="section section-link"><div data-v-d0eb2184="" class="step"><div data-v-d0eb2184="" class="step-btn">33</div></div><div data-v-d0eb2184="" class="center"><div data-v-d0eb2184="" class="title">如何写好一封简历</div><!----><!----></div><!----></a><a data-v-d0eb2184="" class="section section-link"><div 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class="nav-menu-item-group"><li data-v-e1714a36="" class="nav-menu-item"><a data-v-e1714a36=""><i data-v-e1714a36="" class="fengwei fw-logout"></i><span data-v-e1714a36="">登出</span></a></li></ul></div></div><!----></div><!----></div><div data-v-25b273c2="" class="book-body transition--next"><div data-v-b0f6a942="" data-v-25b273c2="" class="section-view book-section-content"><div data-v-ecce5e7e="" data-v-b0f6a942="" class="section-content"><div data-v-ecce5e7e="" class="section-page book-section-view"><div data-v-ecce5e7e="" class="entry-content article-content"><h1 class="heading" data-id="heading-0">安全防范知识点</h1>
<p>这一章我们将来学习安全防范这一块的知识点。总的来说安全是很复杂的一个领域，不可能通过一个章节就能学习到这部分的内容。在这一章节中，我们会学习到常见的一些安全问题及如何防范的内容，在当下其实安全问题越来越重要，已经逐渐成为前端开发必备的技能了。</p>
<h2 class="heading" data-id="heading-1">XSS</h2>
<blockquote class="warning"><p>涉及面试题：什么是 XSS 攻击？如何防范 XSS 攻击？什么是 CSP？
</p></blockquote><p>XSS 简单点来说，就是攻击者想尽一切办法将可以执行的代码注入到网页中。</p>
<p>XSS 可以分为多种类型，但是总体上我认为分为两类：<strong>持久型和非持久型</strong>。</p>
<p>持久型也就是攻击的代码被服务端写入进<strong>数据库</strong>中，这种攻击危害性很大，因为如果网站访问量很大的话，就会导致大量正常访问页面的用户都受到攻击。</p>
<p>举个例子，对于评论功能来说，就得防范持久型 XSS 攻击，因为我可以在评论中输入以下内容</p>
<p></p><figure><img class="lazyload inited loaded" data-src="https://user-gold-cdn.xitu.io/2018/12/2/1676a843648d488c?imageView2/0/w/1280/h/960/format/webp/ignore-error/1" data-width="1280" data-height="301" src="./14.安全防范知识点_files/1676a843648d488c"><figcaption></figcaption></figure><p></p>
<p>这种情况如果前后端没有做好防御的话，这段评论就会被存储到数据库中，这样每个打开该页面的用户都会被攻击到。</p>
<p>非持久型相比于前者危害就小的多了，一般通过<strong>修改 URL 参数</strong>的方式加入攻击代码，诱导用户访问链接从而进行攻击。</p>
<p>举个例子，如果页面需要从 URL 中获取某些参数作为内容的话，不经过过滤就会导致攻击代码被执行</p>
<pre><code class="hljs html" lang="html"><span class="hljs-comment">&lt;!-- http://www.domain.com?name=&lt;script&gt;alert(1)&lt;/script&gt; --&gt;</span>
<span class="hljs-tag">&lt;<span class="hljs-name">div</span>&gt;</span>{{name}}<span class="hljs-tag">&lt;/<span class="hljs-name">div</span>&gt;</span>                                                  
</code></pre><p>但是对于这种攻击方式来说，如果用户使用 Chrome 这类浏览器的话，浏览器就能自动帮助用户防御攻击。但是我们不能因此就不防御此类攻击了，因为我不能确保用户都使用了该类浏览器。</p>
<p></p><figure><img class="lazyload inited" data-src="https://user-gold-cdn.xitu.io/2018/12/2/1676d5e1a09c8367?imageView2/0/w/1280/h/960/format/webp/ignore-error/1" data-width="647" data-height="292" src="data:image/svg+xml;utf8,&lt;?xml version=&quot;1.0&quot;?&gt;&lt;svg xmlns=&quot;http://www.w3.org/2000/svg&quot; version=&quot;1.1&quot; width=&quot;647&quot; height=&quot;292&quot;&gt;&lt;/svg&gt;"><figcaption></figcaption></figure><p></p>
<p>对于 XSS 攻击来说，通常有两种方式可以用来防御。</p>
<h3 class="heading" data-id="heading-2">转义字符</h3>
<p>首先，对于用户的输入应该是永远不信任的。最普遍的做法就是转义输入输出的内容，对于引号、尖括号、斜杠进行转义</p>
<pre><code class="hljs js" lang="js"><span class="hljs-function"><span class="hljs-keyword">function</span> <span class="hljs-title">escape</span>(<span class="hljs-params">str</span>) </span>{
  str = str.replace(<span class="hljs-regexp">/&amp;/g</span>, <span class="hljs-string">'&amp;amp;'</span>)
  str = str.replace(<span class="hljs-regexp">/&lt;/g</span>, <span class="hljs-string">'&amp;lt;'</span>)
  str = str.replace(<span class="hljs-regexp">/&gt;/g</span>, <span class="hljs-string">'&amp;gt;'</span>)
  str = str.replace(<span class="hljs-regexp">/"/g</span>, <span class="hljs-string">'&amp;quto;'</span>)
  str = str.replace(<span class="hljs-regexp">/'/g</span>, <span class="hljs-string">'&amp;#39;'</span>)
  str = str.replace(<span class="hljs-regexp">/`/g</span>, <span class="hljs-string">'&amp;#96;'</span>)
  str = str.replace(<span class="hljs-regexp">/\//g</span>, <span class="hljs-string">'&amp;#x2F;'</span>)
  <span class="hljs-keyword">return</span> str
}
</code></pre><p>通过转义可以将攻击代码 <code>&lt;script&gt;alert(1)&lt;/script&gt;</code> 变成</p>
<pre><code class="hljs js" lang="js"><span class="hljs-comment">// -&gt; &amp;lt;script&amp;gt;alert(1)&amp;lt;&amp;#x2F;script&amp;gt;</span>
<span class="hljs-built_in">escape</span>(<span class="hljs-string">'&lt;script&gt;alert(1)&lt;/script&gt;'</span>)
</code></pre><p>但是对于显示富文本来说，显然不能通过上面的办法来转义所有字符，因为这样会把需要的格式也过滤掉。对于这种情况，通常采用白名单过滤的办法，当然也可以通过黑名单过滤，但是考虑到需要过滤的标签和标签属性实在太多，更加推荐使用白名单的方式。</p>
<pre><code class="hljs js" lang="js"><span class="hljs-keyword">const</span> xss = <span class="hljs-built_in">require</span>(<span class="hljs-string">'xss'</span>)
<span class="hljs-keyword">let</span> html = xss(<span class="hljs-string">'&lt;h1 id="title"&gt;XSS Demo&lt;/h1&gt;&lt;script&gt;alert("xss");&lt;/script&gt;'</span>)
<span class="hljs-comment">// -&gt; &lt;h1&gt;XSS Demo&lt;/h1&gt;&amp;lt;script&amp;gt;alert("xss");&amp;lt;/script&amp;gt;</span>
<span class="hljs-built_in">console</span>.log(html)
</code></pre><p>以上示例使用了 <code>js-xss</code> 来实现，可以看到在输出中保留了 <code>h1</code> 标签且过滤了 <code>script</code> 标签。</p>
<h3 class="heading" data-id="heading-3">CSP</h3>
<p>CSP 本质上就是建立白名单，开发者明确告诉浏览器哪些外部资源可以加载和执行。我们只需要配置规则，如何拦截是由浏览器自己实现的。我们可以通过这种方式来尽量减少 XSS 攻击。</p>
<p>通常可以通过两种方式来开启 CSP：</p>
<ol>
<li>设置 HTTP Header 中的 <code>Content-Security-Policy</code></li>
<li>设置 <code>meta</code> 标签的方式 <code>&lt;meta http-equiv="Content-Security-Policy"&gt;</code></li>
</ol>
<p>这里以设置 HTTP Header 来举例</p>
<ul>
<li>
<p>只允许加载本站资源</p>
<pre><code class="hljs http" lang="http"><span class="hljs-attribute">Content-Security-Policy</span>: default-src ‘self’
</code></pre></li>
<li>
<p>只允许加载 HTTPS 协议图片</p>
<pre><code class="hljs http" lang="http"><span class="hljs-attribute">Content-Security-Policy</span>: img-src https://*
</code></pre></li>
<li>
<p>允许加载任何来源框架</p>
<pre><code class="hljs http" lang="http"><span class="hljs-attribute">Content-Security-Policy</span>: child-src 'none'
</code></pre></li>
</ul>
<p>当然可以设置的属性远不止这些，你可以通过查阅 <a target="_blank" href="https://link.juejin.im/?target=https%3A%2F%2Fdeveloper.mozilla.org%2Fen-US%2Fdocs%2FWeb%2FHTTP%2FHeaders%2FContent-Security-Policy" rel="nofollow noopener noreferrer">文档</a> 的方式来学习，这里就不过多赘述其他的属性了。</p>
<p>对于这种方式来说，只要开发者配置了正确的规则，那么即使网站存在漏洞，攻击者也不能执行它的攻击代码，并且 CSP 的兼容性也不错。</p>
<p></p><figure><img class="lazyload inited" data-src="https://user-gold-cdn.xitu.io/2018/12/2/1676d8215a3d1f5b?imageView2/0/w/1280/h/960/format/webp/ignore-error/1" data-width="1266" data-height="478" src="data:image/svg+xml;utf8,&lt;?xml version=&quot;1.0&quot;?&gt;&lt;svg xmlns=&quot;http://www.w3.org/2000/svg&quot; version=&quot;1.1&quot; width=&quot;1266&quot; height=&quot;478&quot;&gt;&lt;/svg&gt;"><figcaption></figcaption></figure><p></p>
<h2 class="heading" data-id="heading-4">CSRF</h2>
<blockquote class="warning"><p>涉及面试题：什么是 CSRF 攻击？如何防范 CSRF 攻击？
</p></blockquote><p>CSRF 中文名为跨站请求伪造。原理就是攻击者构造出一个后端请求地址，诱导用户点击或者通过某些途径自动发起请求。如果用户是在登录状态下的话，后端就以为是用户在操作，从而进行相应的逻辑。</p>
<p>举个例子，假设网站中有一个通过 <code>GET</code> 请求提交用户评论的接口，那么攻击者就可以在钓鱼网站中加入一个图片，图片的地址就是评论接口</p>
<pre><code class="hljs html" lang="html"><span class="hljs-tag">&lt;<span class="hljs-name">img</span> <span class="hljs-attr">src</span>=<span class="hljs-string">"http://www.domain.com/xxx?comment='attack'"</span>/&gt;</span>
</code></pre><p>那么你是否会想到使用 <code>POST</code> 方式提交请求是不是就没有这个问题了呢？其实并不是，使用这种方式也不是百分百安全的，攻击者同样可以诱导用户进入某个页面，在页面中通过表单提交 <code>POST</code> 请求。</p>
<h3 class="heading" data-id="heading-5">如何防御</h3>
<p>防范 CSRF 攻击可以遵循以下几种规则：</p>
<ol>
<li>Get 请求不对数据进行修改</li>
<li>不让第三方网站访问到用户 Cookie</li>
<li>阻止第三方网站请求接口</li>
<li>请求时附带验证信息，比如验证码或者 Token</li>
</ol>
<h4 class="heading" data-id="heading-6">SameSite</h4>
<p>可以对 Cookie 设置 <code>SameSite</code> 属性。该属性表示 Cookie 不随着跨域请求发送，可以很大程度减少 CSRF 的攻击，但是该属性目前并不是所有浏览器都兼容。</p>
<h4 class="heading" data-id="heading-7">验证 Referer</h4>
<p>对于需要防范 CSRF 的请求，我们可以通过验证 Referer 来判断该请求是否为第三方网站发起的。</p>
<h4 class="heading" data-id="heading-8">Token</h4>
<p>服务器下发一个随机 Token，每次发起请求时将 Token 携带上，服务器验证 Token 是否有效。</p>
<h2 class="heading" data-id="heading-9">点击劫持</h2>
<blockquote class="warning"><p>涉及面试题：什么是点击劫持？如何防范点击劫持？
</p></blockquote><p>点击劫持是一种视觉欺骗的攻击手段。攻击者将需要攻击的网站通过 <code>iframe</code> 嵌套的方式嵌入自己的网页中，并将 <code>iframe</code> 设置为透明，在页面中透出一个按钮诱导用户点击。</p>
<p></p><figure><img class="lazyload inited" data-src="https://user-gold-cdn.xitu.io/2018/12/1/16768734d57c5f47?imageView2/0/w/1280/h/960/format/webp/ignore-error/1" data-width="812" data-height="424" src="data:image/svg+xml;utf8,&lt;?xml version=&quot;1.0&quot;?&gt;&lt;svg xmlns=&quot;http://www.w3.org/2000/svg&quot; version=&quot;1.1&quot; width=&quot;812&quot; height=&quot;424&quot;&gt;&lt;/svg&gt;"><figcaption></figcaption></figure><p></p>
<p>对于这种攻击方式，推荐防御的方法有两种。</p>
<h3 class="heading" data-id="heading-10">X-FRAME-OPTIONS</h3>
<p><code>X-FRAME-OPTIONS</code> 是一个 HTTP 响应头，在现代浏览器有一个很好的支持。这个 HTTP 响应头 就是为了防御用 <code>iframe</code> 嵌套的点击劫持攻击。</p>
<p>该响应头有三个值可选，分别是</p>
<ul>
<li><code>DENY</code>，表示页面不允许通过 <code>iframe</code> 的方式展示</li>
<li><code>SAMEORIGIN</code>，表示页面可以在相同域名下通过 <code>iframe</code> 的方式展示</li>
<li><code>ALLOW-FROM</code>，表示页面可以在指定来源的 <code>iframe</code> 中展示</li>
</ul>
<h3 class="heading" data-id="heading-11">JS 防御</h3>
<p>对于某些远古浏览器来说，并不能支持上面的这种方式，那我们只有通过 JS 的方式来防御点击劫持了。</p>
<pre><code class="hljs html" lang="html"><span class="hljs-tag">&lt;<span class="hljs-name">head</span>&gt;</span>
  <span class="hljs-tag">&lt;<span class="hljs-name">style</span> <span class="hljs-attr">id</span>=<span class="hljs-string">"click-jack"</span>&gt;</span><span class="css">
    <span class="hljs-selector-tag">html</span> {
      <span class="hljs-attribute">display</span>: none <span class="hljs-meta">!important</span>;
    }
  </span><span class="hljs-tag">&lt;/<span class="hljs-name">style</span>&gt;</span>
<span class="hljs-tag">&lt;/<span class="hljs-name">head</span>&gt;</span>
<span class="hljs-tag">&lt;<span class="hljs-name">body</span>&gt;</span>
  <span class="hljs-tag">&lt;<span class="hljs-name">script</span>&gt;</span><span class="javascript">
    <span class="hljs-keyword">if</span> (self == top) {
      <span class="hljs-keyword">var</span> style = <span class="hljs-built_in">document</span>.getElementById(<span class="hljs-string">'click-jack'</span>)
      <span class="hljs-built_in">document</span>.body.removeChild(style)
    } <span class="hljs-keyword">else</span> {
      top.location = self.location
    }
  </span><span class="hljs-tag">&lt;/<span class="hljs-name">script</span>&gt;</span>
<span class="hljs-tag">&lt;/<span class="hljs-name">body</span>&gt;</span>
</code></pre><p>以上代码的作用就是当通过 <code>iframe</code> 的方式加载页面时，攻击者的网页直接不显示所有内容了。</p>
<h2 class="heading" data-id="heading-12">中间人攻击</h2>
<blockquote class="warning"><p>涉及面试题：什么是中间人攻击？如何防范中间人攻击？
</p></blockquote><p>中间人攻击是攻击方同时与服务端和客户端建立起了连接，并让对方认为连接是安全的，但是实际上整个通信过程都被攻击者控制了。攻击者不仅能获得双方的通信信息，还能修改通信信息。</p>
<p>通常来说不建议使用公共的 Wi-Fi，因为很可能就会发生中间人攻击的情况。如果你在通信的过程中涉及到了某些敏感信息，就完全暴露给攻击方了。</p>
<p>当然防御中间人攻击其实并不难，只需要增加一个安全通道来传输信息。HTTPS 就可以用来防御中间人攻击，但是并不是说使用了 HTTPS 就可以高枕无忧了，因为如果你没有完全关闭 HTTP 访问的话，攻击方可以通过某些方式将 HTTPS 降级为 HTTP 从而实现中间人攻击。</p>
<h2 class="heading" data-id="heading-13">小结</h2>
<p>在这一章中，我们学习到了一些常见的前端安全方面的知识及如何防御这些攻击。但是安全的领域相当大，这些内容只是沧海一粟，如果大家对于安全有兴趣的话，可以阅读 <a target="_blank" href="https://link.juejin.im/?target=https%3A%2F%2Fgithub.com%2Ftrimstray%2Fthe-book-of-secret-knowledge" rel="nofollow noopener noreferrer">这个仓库的内容</a> 来学习和实践这方面的知识。</p>
</div><section data-v-ecce5e7e="" class="book-comments"><div data-v-ecce5e7e="" class="box-title">留言</div><div data-v-ecce5e7e="" class="comment-box"><div data-v-1146c0e6="" data-v-ecce5e7e="" class="comment-form comment-form" id="comment"><div data-v-57c47624="" data-v-cf310dfc="" data-v-1146c0e6="" data-src="https://avatars0.githubusercontent.com/u/33979626?v=4" class="lazy avatar avatar loaded" style="background-image: url(&quot;https://avatars0.githubusercontent.com/u/33979626?v=4&quot;);"></div><textarea data-v-1146c0e6="" placeholder="评论将在后台进行审核，审核通过后对所有人可见" class="content-input" style="overflow: hidden; overflow-wrap: break-word; height: 60px;"></textarea><div data-v-1146c0e6="" class="action-box" style="display: none;"><div data-v-627e3889="" data-v-1146c0e6="" class="image-uploader image-uploader" style="display: none;"><input data-v-627e3889="" type="file" class="input"><button data-v-627e3889="" class="upload-btn"><i data-v-627e3889="" class="icon ion-image"></i><span 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data-v-38783431="" class="content-html">一般的react是不是能防范 xss攻击； 而写在dangerousSetInnerHtml 属性里的会容易被攻击；这个属性的原理又是什么啦？</span><!----></div><div data-v-38783431="" class="footer"><button data-v-38783431="" class="like-btn"><i data-v-38783431="" class="collection-arrow-ion ion-arrow-up-b"></i><span data-v-38783431="">0</span></button><span data-v-38783431="" class="sub-comment-btn text-pointer"><span data-v-38783431="" class="title">评论</span><div data-v-38783431="" class="sub-comment--arrow" style="display: none;"></div></span><span data-v-38783431="" class="date">5天前</span><!----></div><!----></div><!----></div></li><li data-v-6adae277="" class="item"><div data-v-38783431="" data-v-6adae277="" class="comment"><div data-v-3a6943ce="" data-v-38783431="" st:block="userPopover" st:state="5ac99a916fb9a028e46ee753" class="user-popover-box"><!----><a data-v-38783431="" href="https://juejin.im/user/5ac99a916fb9a028e46ee753" target="_blank" rel="" data-v-3a6943ce=""><div data-v-57c47624="" 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1</span><!----></div><div data-v-38783431="" class="footer"><button data-v-38783431="" class="like-btn"><i data-v-38783431="" class="collection-arrow-ion ion-arrow-up-b"></i><span data-v-38783431="">0</span></button><span data-v-38783431="" class="sub-comment-btn text-pointer"><span data-v-38783431="" class="title">评论</span><div data-v-38783431="" class="sub-comment--arrow" style="display: none;"></div></span><span data-v-38783431="" class="date">12天前</span><!----></div><!----></div><!----></div></li><li data-v-6adae277="" class="item"><div data-v-38783431="" data-v-6adae277="" class="comment"><div data-v-3a6943ce="" data-v-38783431="" st:block="userPopover" st:state="5bfe2b9d51882556782cb45c" class="user-popover-box"><!----><a data-v-38783431="" href="https://juejin.im/user/5bfe2b9d51882556782cb45c" target="_blank" rel="" data-v-3a6943ce=""><div data-v-57c47624="" data-v-cf310dfc="" data-v-38783431="" data-src="https://thirdwx.qlogo.cn/mmopen/vi_32/Q0j4TwGTfTL5hCqcVuQCbelgWE29N5qKlqZoC9UPeCHBQMW3RLymKbvYibxoVWlTJOOX5B5ibJPKMO6OLdMT2E4A/132" class="lazy avatar avatar" style="background-image: none;"></div></a></div><div data-v-38783431="" class="content-box"><div data-v-38783431="" class="header"><div data-v-38783431="" class="user-info"><div data-v-3a6943ce="" data-v-38783431="" st:block="userPopover" st:state="5bfe2b9d51882556782cb45c" class="user-popover-box"><!----><a data-v-38783431="" href="https://juejin.im/user/5bfe2b9d51882556782cb45c" target="_blank" rel="" class="username" data-v-3a6943ce="">🍒</a></div><div data-v-38783431="" class="position"></div></div></div><div data-v-38783431="" class="content"><!----><span data-v-38783431="" class="content-html">&lt;script&gt;alert(1)&lt;/script&gt;</span><!----></div><div data-v-38783431="" class="footer"><button data-v-38783431="" class="like-btn"><i data-v-38783431="" class="collection-arrow-ion ion-arrow-up-b"></i><span data-v-38783431="">0</span></button><span data-v-38783431="" class="sub-comment-btn text-pointer"><span data-v-38783431="" class="title">评论</span><div data-v-38783431="" class="sub-comment--arrow" style="display: none;"></div></span><span data-v-38783431="" class="date">12天前</span><!----></div><!----></div><!----></div></li><li data-v-6adae277="" class="item"><div data-v-38783431="" data-v-6adae277="" class="comment"><div data-v-3a6943ce="" data-v-38783431="" st:block="userPopover" st:state="587c5fe7570c352201049fdd" class="user-popover-box"><!----><a data-v-38783431="" href="https://juejin.im/user/587c5fe7570c352201049fdd" target="_blank" rel="" data-v-3a6943ce=""><div data-v-57c47624="" data-v-cf310dfc="" data-v-38783431="" data-src="https://user-gold-cdn.xitu.io/2018/11/18/16726f66e0589748?imageView2/1/w/100/h/100/q/85/format/webp/interlace/1" class="lazy avatar avatar" style="background-image: none;"></div></a></div><div data-v-38783431="" class="content-box"><div data-v-38783431="" class="header"><div data-v-38783431="" class="user-info"><div data-v-3a6943ce="" data-v-38783431="" st:block="userPopover" st:state="587c5fe7570c352201049fdd" class="user-popover-box"><!----><a data-v-38783431="" href="https://juejin.im/user/587c5fe7570c352201049fdd" target="_blank" rel="" class="username" data-v-3a6943ce="">海王</a></div><div data-v-38783431="" class="position">FE</div></div></div><div data-v-38783431="" class="content"><!----><span data-v-38783431="" class="content-html">&lt;img src="null" onerror="javascript:alert(1);"&gt;</span><!----></div><div data-v-38783431="" class="footer"><button data-v-38783431="" class="like-btn"><i data-v-38783431="" class="collection-arrow-ion ion-arrow-up-b"></i><span data-v-38783431="">0</span></button><span data-v-38783431="" class="sub-comment-btn text-pointer"><span data-v-38783431="" class="title">评论</span><div data-v-38783431="" class="sub-comment--arrow" style="display: none;"></div></span><span data-v-38783431="" class="date">12天前</span><!----></div><!----></div><!----></div></li><li data-v-6adae277="" class="item"><div data-v-38783431="" data-v-6adae277="" class="comment"><div data-v-3a6943ce="" data-v-38783431="" st:block="userPopover" st:state="5c1cb36d6fb9a049c965a80a" class="user-popover-box"><!----><a data-v-38783431="" href="https://juejin.im/user/5c1cb36d6fb9a049c965a80a" target="_blank" rel="" data-v-3a6943ce=""><div data-v-57c47624="" data-v-cf310dfc="" data-v-38783431="" data-src="https://thirdwx.qlogo.cn/mmopen/vi_32/Q0j4TwGTfTL574bGDoic7uzzfwek3Zvot2t0ViarxoXFDHea9YVee1TvGBnmcXbdic65CEPOgUh6okThY1mYva0Ng/132" class="lazy avatar avatar" style="background-image: none;"></div></a></div><div data-v-38783431="" class="content-box"><div data-v-38783431="" class="header"><div data-v-38783431="" class="user-info"><div data-v-3a6943ce="" data-v-38783431="" st:block="userPopover" st:state="5c1cb36d6fb9a049c965a80a" class="user-popover-box"><!----><a data-v-38783431="" href="https://juejin.im/user/5c1cb36d6fb9a049c965a80a" target="_blank" rel="" class="username" data-v-3a6943ce="">小米dds</a></div><div data-v-38783431="" class="position"></div></div></div><div data-v-38783431="" class="content"><!----><span data-v-38783431="" class="content-html">&lt;script&gt;alert(1)&lt;/script&gt;</span><!----></div><div data-v-38783431="" class="footer"><button data-v-38783431="" class="like-btn"><i data-v-38783431="" class="collection-arrow-ion ion-arrow-up-b"></i><span data-v-38783431="">0</span></button><span data-v-38783431="" class="sub-comment-btn text-pointer"><span data-v-38783431="" class="title">评论</span><div data-v-38783431="" class="sub-comment--arrow" style="display: none;"></div></span><span data-v-38783431="" class="date">13天前</span><!----></div><!----></div><!----></div></li><li data-v-6adae277="" class="item"><div data-v-38783431="" data-v-6adae277="" class="comment"><div data-v-3a6943ce="" data-v-38783431="" st:block="userPopover" 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class="content-html">&lt;script&gt;alert(1)&lt;/script&gt;</span><!----></div><div data-v-38783431="" class="footer"><button data-v-38783431="" class="like-btn"><i data-v-38783431="" class="collection-arrow-ion ion-arrow-up-b"></i><span data-v-38783431="">0</span></button><span data-v-38783431="" class="sub-comment-btn text-pointer"><span data-v-38783431="" class="title">评论</span><div data-v-38783431="" class="sub-comment--arrow" style="display: none;"></div></span><span data-v-38783431="" class="date">14天前</span><!----></div><!----></div><!----></div></li><li data-v-6adae277="" class="item"><div data-v-38783431="" data-v-6adae277="" class="comment"><div data-v-3a6943ce="" data-v-38783431="" st:block="userPopover" st:state="584cdf9c0ce463005c5aaf1d" class="user-popover-box"><!----><a data-v-38783431="" href="https://juejin.im/user/584cdf9c0ce463005c5aaf1d" target="_blank" rel="" data-v-3a6943ce=""><div data-v-57c47624="" data-v-cf310dfc="" data-v-38783431="" data-src="https://b-gold-cdn.xitu.io/v3/static/img/default-avatar.e30559a.svg" class="lazy avatar avatar" style="background-image: none;"></div></a></div><div data-v-38783431="" class="content-box"><div data-v-38783431="" class="header"><div data-v-38783431="" class="user-info"><div data-v-3a6943ce="" data-v-38783431="" st:block="userPopover" st:state="584cdf9c0ce463005c5aaf1d" class="user-popover-box"><!----><a data-v-38783431="" href="https://juejin.im/user/584cdf9c0ce463005c5aaf1d" target="_blank" rel="" class="username" data-v-3a6943ce="">一波万波</a></div><div data-v-38783431="" class="position"></div></div></div><div data-v-38783431="" class="content"><!----><span data-v-38783431="" class="content-html">&lt;script&gt;alert(1)&lt;/script&gt;</span><!----></div><div data-v-38783431="" class="footer"><button data-v-38783431="" class="like-btn"><i data-v-38783431="" class="collection-arrow-ion ion-arrow-up-b"></i><span data-v-38783431="">0</span></button><span data-v-38783431="" class="sub-comment-btn text-pointer"><span data-v-38783431="" class="title">评论</span><div data-v-38783431="" class="sub-comment--arrow" style="display: none;"></div></span><span data-v-38783431="" class="date">15天前</span><!----></div><!----></div><!----></div></li><li data-v-6adae277="" class="item"><div data-v-38783431="" data-v-6adae277="" class="comment"><div data-v-3a6943ce="" data-v-38783431="" st:block="userPopover" st:state="599e6626f265da24903500d7" class="user-popover-box"><!----><a data-v-38783431="" href="https://juejin.im/user/599e6626f265da24903500d7" target="_blank" rel="" data-v-3a6943ce=""><div data-v-57c47624="" data-v-cf310dfc="" data-v-38783431="" data-src="https://user-gold-cdn.xitu.io/2018/7/16/164a0fa0fad2df1f?imageView2/1/w/100/h/100/q/85/format/webp/interlace/1" class="lazy avatar avatar" style="background-image: none;"></div></a></div><div data-v-38783431="" class="content-box"><div data-v-38783431="" class="header"><div data-v-38783431="" class="user-info"><div data-v-3a6943ce="" data-v-38783431="" st:block="userPopover" st:state="599e6626f265da24903500d7" class="user-popover-box"><!----><a data-v-38783431="" href="https://juejin.im/user/599e6626f265da24903500d7" target="_blank" rel="" class="username" data-v-3a6943ce="">MioGo</a></div><div data-v-38783431="" class="position">小前端 @ 某汽车相关公司的IT部门</div></div></div><div data-v-38783431="" class="content"><!----><span data-v-38783431="" class="content-html">&lt;script&gt;alert(1)&lt;/script&gt;</span><!----></div><div data-v-38783431="" class="footer"><button data-v-38783431="" class="like-btn"><i data-v-38783431="" class="collection-arrow-ion ion-arrow-up-b"></i><span data-v-38783431="">0</span></button><span data-v-38783431="" class="sub-comment-btn text-pointer"><span data-v-38783431="" class="title">评论</span><div data-v-38783431="" class="sub-comment--arrow" style="display: none;"></div></span><span data-v-38783431="" class="date">23天前</span><!----></div><!----></div><!----></div></li><li data-v-6adae277="" class="item"><div data-v-38783431="" data-v-6adae277="" class="comment"><div data-v-3a6943ce="" data-v-38783431="" st:block="userPopover" st:state="5c073e8cf265da611204cb99" class="user-popover-box"><!----><a data-v-38783431="" href="https://juejin.im/user/5c073e8cf265da611204cb99" target="_blank" rel="" data-v-3a6943ce=""><div data-v-57c47624="" data-v-cf310dfc="" data-v-38783431="" data-src="https://thirdwx.qlogo.cn/mmopen/vi_32/dkic0WodNXYWCcHTlGicXdia2sKgLtlUtQFGemmm1CV6SwGGcE2M4QKdic35oPDqgcsnra4ibz7b89qKkRlQwImRvwQ/132" class="lazy avatar avatar" style="background-image: none;"></div></a></div><div data-v-38783431="" class="content-box"><div data-v-38783431="" class="header"><div data-v-38783431="" class="user-info"><div data-v-3a6943ce="" data-v-38783431="" st:block="userPopover" st:state="5c073e8cf265da611204cb99" class="user-popover-box"><!----><a data-v-38783431="" href="https://juejin.im/user/5c073e8cf265da611204cb99" target="_blank" rel="" class="username" data-v-3a6943ce="">云不想说话l</a></div><div data-v-38783431="" class="position"></div></div></div><div data-v-38783431="" class="content"><!----><span data-v-38783431="" class="content-html">&lt;script&gt;alert(1)&lt;/script&gt;</span><!----></div><div data-v-38783431="" class="footer"><button data-v-38783431="" class="like-btn"><i data-v-38783431="" class="collection-arrow-ion ion-arrow-up-b"></i><span data-v-38783431="">2</span></button><span data-v-38783431="" class="sub-comment-btn text-pointer"><span data-v-38783431="" class="title">评论</span><div data-v-38783431="" class="sub-comment--arrow" style="display: none;"></div></span><span data-v-38783431="" class="date">29天前</span><!----></div><!----></div><!----></div></li><!----></ul></section></div></div><!----><!----></div></div><div data-v-06852630="" data-v-25b273c2="" class="book-handle book-direction" style=""><div data-v-06852630="" 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